p12 20v head solenoid

[BEXE]

I'd appreciate it. I feel like its gonna be a pain to source them.

[jr_ss]

I'd appreciate it. I feel like its gonna be a pain to source them.

Here you go Dave...





If you need anything else let me know, I'll see what I can do.

[BEXE]

Thanks brother! Off to pull-a-part I go!

[Tower240sx]

I'm almost certain that they will only slide out the front of the head, but how tight is the sealing around the rocker shaft? I guess it's plausible, but like you said, you'd have to mess with one to find out.

Mike, care to chime in?

They actually slide out the rear, there is a 5mm bolt that locates them at the first cam journal on each side remove those, the plate pictured above, and the 10mm (allen) plug behind the exhaust shaft and both should slide out freeing the rockers.


I have those pigtails somewhere if they are that hard to locate.


I make a plate that bolts over that whole area and feeds oil directly to the intake rocker shaft for actuation and thru the passage in the stock head for exhaust actuation.


Def is correct, or atleast he assumes I am, I do not use a bleed back other than what is in the rocker shaft. we tested bleed down rate by turning them on at a low RPM then back off a couple thousand rpm later, the fuel demand in AEM log was apparent almost instantly. so we decided no further complication was needed.

[nicknack]

I put a p12 solenoid on my p11 head. I carved out the channel for the oil drain (stupidly) not realising I could rely on the rockers draining themselves. That meant I had to block off the hole circled in red as it overlaps with the drain hole on the head.

Wasn't much work in total. Maybe an hour total. The fitting is a 1/8 npt to an6.

[Def]

How is the firewall clearance with the P12 VVL solenoid on an S13? It doesn't look like it's much wider than the Mazworx blocks with fittings on them.

[Def]

BTW - does the top bolt thread in on the P12 solenoid on a P11 head?

[jr_ss]

It looks like the P12 solenoid would occupy the same area the bulkhead ridge would on an S14. As much as I like the simplicity of the P12 single solenoid, I do like the idea/capability of switching the cams at different rpms to help spool though.

[Def]

It looks like the P12 solenoid would occupy the same area the bulkhead ridge would on an S14. As much as I like the simplicity of the P12 single solenoid, I do like the idea/capability of switching the cams at different rpms to help spool though.

Seems like everybody just switches cams at basically the same RPM. I was planning to wire it all up to one wire personally, but I guess I could do two.

[jr_ss]

Seems like everybody just switches cams at basically the same RPM. I was planning to wire it all up to one wire personally, but I guess I could do two.

Yes, it does seem like most do, which seems a bit odd. I would think that to optimize the setup you'd want that functionality. To each their own I guess, I opted to keep mine seperate. I'll see what the tuner wants to do and if switching the exhaust before the intake aids in spool time. I would think with the P11 cams it would, however, the P12 cams it may be a negligible increase.

[Tower240sx]

Yes, it does seem like most do, which seems a bit odd. I would think that to optimize the setup you'd want that functionality. To each their own I guess, I opted to keep mine seperate. I'll see what the tuner wants to do and if switching the exhaust before the intake aids in spool time. I would think with the P11 cams it would, however, the P12 cams it may be a negligible increase.

My switches are independently controlled in AEM, but in the tuning process (which was not rushed in any way---free dyno time, free tuning) we found that there was no gain from the exhaust cam until the intake cam was activated, but I wouldn't expect the scenario to play out the same for all setups. what little difference we maintained in the switchover rpm was related to not wanting to hit the oil system with both duties at the same instant, i think my cams switch within a couple hundred rpm 500 max.

if anything switching the intake cam first drops boost in the manifold and may make better power momentarily because it would decrease the required torque on the turbine shaft, then with enough testing you will know how long the benefit of concentrated exhaust pulses from a shorter exhaust event is greater than the drawback of charge dilution and increased effort on the exhaust stroke...so in this way a high comp small turbo motor like my setup may want different things than a low compression (or reasonable compression) big turbo motor...or with bigger cams...or valve and headwork...or manifold ...or ...or ........or ...squirrel

[nicknack]

The p12 solenoid was thinner than the p12 CAS. The solenoid has heaps of clearance, but the plug is very close because of the motor angling back

I'm not too fussed on switching the cams independently because I probably won't fall below the switch point on the track so realistically it'd only help me on the street slightly.

I can't comment about the clearance on a s13. But this is a s15 with stock engine mounts.

[Tower240sx]

That is a good point aswell, with the broad power band of the motor you are never really stuck down below the switch point, on stock cams atleast.

[Def]

According to the FWD guys, even N1 cams get switched early with boost. They switch them right as spool up happens, and it really helps spool (probably due to early blow down).

I think I remember a comparison where N1 cams spooled up a turbo faster than P11 cams due to the large exhaust duration/lift.

[nicknack]

the setup I was running a couple of months ago felt strongest switching around 3800. The car immediately and noticeably pulled harder when they switched. This was p11 cams with a td06. It'll be interesting to see where the switch point will end up with p11 cams and the twin scroll 7163. i'm guessing low to mid 4000s.